Question

anne picks a 4-digit number the first number is not 0 the four digit number is a multiple of 5 how many different 4-digit numbers could she pick?

Answer 1

The first digit of a number can be 1-9. The 2nd and the 3rd digit can be 1-10. The last digit can be 0 or 5 ( 2 numbers ):
9 * 10 * 10 * 2 = 1,800
She could pick 1,800 different 4-digit numbers.